As set forth in Japanese Application Patent Laid-Open Publication No. Hei 07-134767, the art for conducting judgments based on the path information of persons that has been obtained using a video camera is known as a method of judging whether the behavior of persons is abnormal. The above-mentioned prior art assumes that the normal paths of persons are free from changes in velocity and acceleration, and judges that the behavior having significant changes in such terms is abnormal.
The above art, however, is intended only to judge whether the behavior itself of persons is abnormal, and does not enable the estimation of the cause or place of abnormal behavior. For example, if an unusual smell occurs in a place and causes the surrounding persons to behave abnormally, although the abnormality of the behavior of these persons can be judged, the place where the unusual smell that has caused the abnormality cannot be estimated.
In order to solve this problem, Japanese Application Patent Laid-Open Publication No. Hei 06-274786 discloses the art for estimating the place of occurrence of the event which has caused the abnormal behavior of the automobiles moving on a road. According to this method, for example, if a stone falls down onto the road, the place of occurrence of the abnormality (namely, the falling stone) can be estimated from the movements of the automobiles taking an avoiding action. That is to say, this method in which the traffic of automobiles is measured using a video camera estimates that the cause of the above-mentioned abnormal behavior of automobiles is present at a place small in their traffic or a place in which their traffic changes significantly.
Under the above prior art, the path of the automobiles moving on the road is accumulated for a fixed time and then the abnormal section is estimated from the frequency distribution obtained. For this reason, there has been the problem that abnormal sections cannot be estimated from momentary information relating to moving objects.
An object of the present invention is to provide a monitoring apparatus that automatically estimates, by using momentary information on moving objects, the place where the abnormal behavior of the moving objects has been caused.